Which of the following machines has high power factor and efficiency under running conditions?

Two-value Capacitor single-phase Induction Motor:

This motor has a cage rotor, and its stator has two windings namely the main winding and the auxiliary winding. The two windings are displaced 90° in space. The motor uses two capacitors C_S and C_R. In the initial stage, the two capacitors are connected in parallel. 

R_M, X_M = Main winding resistance and reactance.

R_A, X_A = Auxiliary winding resistance and reactance.

I_A = Current through the auxiliary winding 

IM = Current through the main winding

V = 1-ϕ supply voltage

C_S = Starting capacitor

C_R = Running capacitor

ϕ = Angle between main winding current and auxiliary winding current.

During starting of motor CS, CR both working so, ϕ is greater than 90° 

During the running of motor only CR is working so, ϕ equals 90° 

Due to this, it has a high power factor and efficiency under running conditions.

Additional Information

Applications:

1. Two-value capacitor motors are used for loads of higher inertia that require frequent start.
2. These are used in pumping equipment.
3.These are used in refrigeration, air compressors, etc.